Thread-grinding machine



Aug. 3 1926.

H. E. DURKEE THREAD GRINDING MACHINE Filed June 6 V19:24 5 Sheets-Sheet 1 Hab/M Aug. 3 1926.

H. E. DURKEE THREAD GRINDNG MACHINE.

5 sheets-sheet z Filed June 6I 1924.

Arrokllfr Aug. 3 i

1,594,407 H. E. DURKEE THREAD GRNDING MACHINE I+ -Filed June 6, 1924.

5 Sheets-Sheet v3 1401755 A TTORNEY Aug. 3, 192e. 1,594,407

H. E. DURKEE THREAD GRINDING MACHINE v Filed June 6 1924. 5 Sheets-Sheet 4 i i 'i El 54 Egeo '50 FWN 56 l: /l/mvma y 55 1 Br WW/L A TTUHNEY Aug'. 3 1926. 1,594,407

H. E. DURKEE THREAD GRINDING MACHINE Filed June s- 1924 5*ShetS-Sheet 5 [NVENTDR B'WyMZ/e.

' Afro/mfr Patented Aug. 3, 1926.

UNITED STATES PATENT OFFICE.

HENRY E. DURKEE, OF GLASTONIB'URY, CONNECTICUT, ASSIGNOR T0 PRATT & WHIT- NEY COMPANYOF NEW YORK, N. Y., A CORPORATION 0F NEW JERSEY.

THREAD-@BINDING MACHINE.

Application led June 6, 1924. Serial No. 718,315.

My invention relates to thread grinding machines and particularly to machines for grinding worm members.

One object of my' invention is to provide an improved, thread grinding machine having a lead'screw aligned with the work carrying spindle and engaging an adjustable two-piece nut. c

Another object of my invention is to provide a grinding machine of the above indicated character that shall grind a worm member in an efficient manner and that shall automatically stop the operation of the machine after a predetermined grinding operation.

A further object of my invention is to provide a thread grinding machine that shall be provided with a lead screw aligned with the work carrying spindle and that shall be provided with improved connecting means between the lead screw ,and the adjacent members to permit an easy removal and replacement of the lead screw and the adjustable nut.

. In grinding a threaded member, such for example as a worm member, it is essential to eliminate lost motion if a grinding operation is to be effected on the :work in both directions of relative movement of the wheel with respect to the work. In a machine such as disclosed in the application, a twopiece nut, which is in engagement with the `lead screw aligned with the work carrying spindle, is adjusted for' wear and insures against lost motion. Moreover, in grinding a piece of work, it is desirable to automatically stop the grinding operation upon finish of the work. In the machine disclosed in the application, means is provided for automatically stopping the operation of the machine` when a predetermined number of grinding operations have been effected on the work piece.

In the accompanying drawings:

. Figure 1 is-a front. elevational view of a machine constructed in accordance with my invention. l

Fig. 2 is a plan view of the machine shown in Fig. 1.

Fig. 3 is a detail view of the feed mechanism.

Fig.- l4 is a sectional view along the line 4-4 of Fig. 3.

Fig. 9 is a detail view of the lead screw and the two-piece nut associated therewith.

Figs. 10 and 11 are detail views of the means for controlling the automatic stopping of the machine.

Fig. 12 is a detail view of the connection between the lead screw and the Work carryino' spindle.

ig. 13 is a sectional view along the line 13-13 of Fig. 2.

Referring to the drawings, the machine.y

is illustrated comprising a main frame 1 on whichl is mounted a workI carrying carriage 2 and a wheel slide 3. The carriage 2 is supported on guideways 4 and 5 and the slide 3 is mounted on guideways 6 andy 7. The slide 3 carries a suitable grinding wheel 8 and the carriage 2 carries a headstock 9 and a tailstock 10.

The tailstock 10 is adjustable on the carriage 2 in any suitable manner. The headstock 9 carries a work spindle 11 which4 is'in n alignment with a lead screw 12. The lead screw 12 is provided with teeth 13 on one end thereof which are adapted to mesh with similar teeth l14 formed on one end of the spindle 11. A collar 15, which is held on the spindle by a shoulder 16, is threadably connected to` the end of the lead screw 12. The collar 15 serves to hold the lead screw and the spindle firmly in engagement with eachother. v

`The lead4 screw 12 and the spindle 1,1 are operated by a motor 17 which is mounted on the main frame of the machine. The motor 17 carries a pinion 18 which meshes with a gear wheel 19. The gear wheel 19l is mounted on a short shaft 20 which carries a pinion 21. The pinion 21 meshes with a gear wheel 22 which is mounted on a 'shaft 23. The shaft 23 carries a clutch member 24 ,and a sleeve member 25. The sleeve member 25 is` rotatably mounted on the shaft 23 and the clutch member 24 is splined to such shaft. The clutch member 24 is holding such provided with suitable clutch teeth which are adapted to engage similar clutch teeth on the sleeve member 25. The clutch member 24 is operated by a bell crank lever 26, in a manner to be hereinafter set forth, to start and stop the operation of the machine.

The sleeve member 25 carries a gear wheel 27 which meshes with a gear wheel 28 on a shaft 29 and with a gear wheel 30 on the shaft 31. The gear wheel 30 is fixedly mounted on the shaft 3l, as shown in Fig. 7 of the drawings, and the gear wheel 28 is rotatably mounted on the shaft 29, as shown in Fig. 8 of the drawings. The shaft 29 carries two other gear wheels 32 and 33. The gear wheel 33 is iixedly mounted on the shaft and the gear wheel is rotatably mounted on such shaft. A clutch member 34, which is mounted on the shaft 29 between ,the gear wheels 28 and 32, serves for connecting'either one of such gear wheels fixedly to the shaft. The clutch member 34 is operated by a yoke member 35 which is pivotally mounted on a shaft 36. An arm 37 projects from the yoke member 34 and carries a roller 38. The roller 38 is fitted to a cam groove 39 which is formed in a cam drum 40 (Figs. 6, 7 and 8). The cam drum 40 is rotatably mounted on the shaft 3l and is disposed adjacent to the gear wheel 30. A gear wheel 4lv is tixedly mounted on the shaft 3l and meshes with the gear wheel 32 which is mounted on the shaft 29.

In the above construction, it will be noted the gear wheels 28 and 32, which are rotatae bly mounted on the shaft 29, are constantly rotated in opposite directions when the clutch member 24 is in an operative position. The gear wheel 28 is connected directly to the shaft 23 through the gear wheel 27 and the sleeve 25. The gear wheel 32 is connected to the shaft 23 through the gear whe l 41, shaft 31', gear wheels 30 and 27, and tie sleeve 25.

A ratchet wheel 42 is Xedly mounted on the shaft-3l between the gear wheel 4l and the cam drum 40. A pawl 43, which is pivotally mounted on the cam drum 40, is pressed by a spring member 44 towards the ratchet wheel. A shoulder 45, which is formed on the pawl 43, is. adapted to be engaged by one of two levers 46 and 47 for awl out of engagement with the ratchet wieel. In Fig. 6 of the drawings, t-he lever 46 is shown in engagement with the shoulder 45 for holding the pawl away from the ratchet wheel 42. The lever 47 is shown in position to engage the shoulder 45 of the pawl when the lever 46 has been moved away from the pawl. In the above construction, it should be noted that when the pawl 43 is in engagement with the ratchet wheel 42, the cam drum 4() is directly connected to the shaft 31 and is rotated therewith. The rotation of the cam drum 40, as heretofore set forth, controls the operation of the clutch member 34 on the shaft 29.

The levers 46 and 47 are respectively mounted on short shafts 5l and 52. The short shafts 5l and 52 extend to the front of the machine and respectively carry levers 53 and 54. A bell crank lever 55, which is pivot'ally mounted on the main frame of the machine, has one ar1n56 extending between the two levers 53 and 54. Accordingly, it is apparent operation of 'the bell crank lever 55 serves to move one of the levers 53 and 54 and accordingly operate one of the levers 46 and 47. If the bell crank lever 55 is operated in the clockwise direction, as shown in Fig. 6 of the drawings, the lever 46 is moved out of engage ment with the shoulder 45 of the pawl 43. The pawl is released to connect the 'cam drum with the ratchet wheel. The cani drum 40 is operated by the ratchet wheel 42 until the pawl 43 is moved out of engagement with the ratchet wheel by the lever 47. The rotation of the cam drum 40, as heretofore set forth, moves the clutch member 34 to connect one of the gear wheels 28 and 32 with theshaft 29.

The bell crank lever 55 is connected to a lever 58 which is pivotally mounted on he main frame as shown in Fig. 6 of the drawings. The lever 58 is connected through a reach rod 59 to a lever 60. The lever 60 is operated by dogs 6l and 62 which are mounted on the carriage y2. The dogs 6l and 62 are held in position by bolts which are secured to aT-slot 63 formed in the carriage. The position of the dogs 6l and 62 on the carriage 2 determines the points on the carriage travel when the direction of rotation of the spindle ll and the lead screw l2will be reversed. The dogs 61 and 62 do not only control thedirection of rotation of the spindle but also reverse the direction of movement of the carriage 2.

The gear wheel 33, which is mounted on the shaft 29, meshes with a gear wheel 64 which is mounted on a shaft 65. The shaft 65 carries apull'ey 66 which is connected by a belt 67 to a pulley 68 on a shaft 69. The shaft 69 carries a spiral gear wheel 7 O which meshes with a spiral gear wheel 7l. A shaft 72, which is splined to the spiral gear wheel 7l, is connected to the lead screw l2 through a suitable coupling 73. The coupling 73, which is best shown in Fig. 9 of the drawings, comprises a member 74 having two T-slots 75 4and 76 formed there'- in at right angles to each other. Two collar members 77 and 78, which are respectively pinned to the shaft 72 and to the lead screw l2, are provided with T-members which fit within the T-slots 75 and 76. As will be more apparent hereinafter, the coupling 73 lll() serves not only' to compensate for small changes inthe alignment of the shaft with the'lead screw but also to ermit a quick removal of the lead screw or replacement purposes.

A suitable nut 7 is mounted on the leadl bracket 81 and held in position by a cap member 82. The bracket 81 is suitably secured to the main frame-1 ofthe machine. The sleeve member is held against lon?.- tudinal` movement in the bracket 81 y means, of a shoulder 83 and a collar 84 which is threadably connected to Within the sleeve member v80 are mounted the threaded portions 85 and 86 of the nut.

The portions 85 and 86 directly engage the threads on the lead screw 12, as shown in Fig. 9 of the drawings. The portion 85 is held securely in position by means of a yset screw 87. The portion 86 may be moved towards the portion 85 by means of a collar 88 which is threaded to the sleeve 83. Thus, by operating the collar 88, the portion 86 may be so moved as to take care of any wear or lost motion. The portions 85- and 86 of thevgnut are preferably composed of Babbitt metal cast 1n bronze rings.

The bell crank lever 26 (Fig. 8) is operated by a lever 90 (Figs. 1 and 6). The lever 90 is operated by an arm 91 which is fixedly mounted on a shaft 92. The shaft 92 extends to the front of the machine and carries an operating arm 93. The operating arm 93 may be operated manually yat will or may be automatically operated in accordance'with the movement of the carriage 2.

The carriage 2 carries a bolt 95 which supports a notched disk 96 and a small ratchet wheel 97 (Figs.` 10 and 11). The disk 96 and the ratchet wheel 97 are rotatably mounted on a sleeve 98 which surrounds the bolt 95. A bracket 99, which is xedly secured to the bolt in any suitable manner is provided with spring pressed detents 100 for engaging orices in the disk 96 to accentuate the positions of the disk and the ratchet wheel. A lever 101 is rotatably mounted on the sleeve 98 adjacent the ratchet wheel 97 and carries a pawl member 102which is adaptedfto engage the teethl of the ratchet member. An arm 103 on the lever 101 is pressed by a spring 104 towards an adjustable stop 105 on the bracket 99. The opposite end of the lever 101 is provided with a roller 106 which is adapted to engage an adjustable dog 107 on the main frame 1 of the machine (Fig. 1). Thus, it is apparent at each longitudinal movement of the carriage 2, the roller 106 engages lthe dog I107 for effecting a small movement of rotation. of the ratchet vwheel 97 and the notched disk 96.-

A pawl member 108 is pivotally mounted on thecarriage 2 and is held in engagement with av riphery of the notched disk 96. One endjo the pawl member. 108 is shaped to fit the notches which are formed in the disk 96. Thus when a notch is moved o posite thc end of the pawl member, the paw mem ber is given asmall movement of rotation so that one end thereof isfinv position to 'engage the end of theoperating handle 93.

The operating handle 93, as heretofore set forth, controls the 'clutch member 24. for

starting and stopping theoperation ofthe y machine. Accordingly, it is apparent the mechanism just described may be so set as to stop the'machine after an redetermined number of reciprocations o t e carriage 2.

The wheel slide 3 carries a bracket 109 which provides suitable bearings for the wheel spindle 110. The wheel spindle 110 carries a pulley 111 which is connected by a belt v112 to a pulley 113 on' a power shaft '114. The belt 112 extends over idler pulleys 115' on the lslide 3 and around an idler pulley 116'on the main frame 1. The pulley 116 isadjustable to take up\any slack that may be produced in the belt. The power shaft 114 carries a second pulley 117 which is connected by 'a belt 118 to a pulley 119 on the shaft of a motor 120. A suitable idler gear wheel 121 is provided for taking up slack in the belt 118.

A feed screw 122, which is mounted lin the main frame 1 of the machine engagesa suitable nut 123 which projects from the and a ratchet wheel 134.I The ratchet Ywheel.

134. may be operated either manually or automatically.

A lever having three arms 135, 136 and 137 is rotably mounted on a bushing y138 which surrounds the shaft 126 (Figs. `1,- 3 andl 4). which is thrown in engagement with the teeth of the ratchetwheel 134 ywhen automatic feeding ofthe wheel slide is desired. The arm 135 may be manually operated to `effect feeding at will and carries a pawl 140 which is thrown in engagement with the teeth whenever feeding at will is desired. The arm 137 is connected by a reach rod 141 to a bell crank lever 142. The hell crank lever 142 carries a rollerr143 which is The arm 136 carries a pawl 139' The adapted to engage adjustable dogs 144 and 145 on the carriage 2 of the machine. The arm 137 and the bell crank lever 142 are preferably .held in a retracted position by means of a spring member 146, as best shown in Fi 3 of the drawings. A screw 147 is pre erably provided for limiting the feeding movement of the arm 137. The dogs 144 and 145 are held in position bymeans of T-bolts which are fitted to the T-slots 63 inthe carriage 2. Such dogs may be adjusted to any desired position along the carriage 2.

A wei ht member 148. is secured to the wheel slie 3 by a cable 149. The cable 149 passes over suitable pulleys 150 exerting a force on the slide 3 to take up any lost motion in the feeding connection. A dressing attachment .151, which ispivotally mounted on the bracket 109, is adapted to be swung into position for truing the grinding wheel 8. The bracket 151 is pivote-d on a shaft 152 and is adapted to engage a. stop member 153 when'in position. A dressing slide 154, which is mounted on the bracket 151, is operated by a hand wheel 155.

Modifications in the machine and in the arrangement Aand location of parts mav be made' within the spirit and scope of my invention and such modifications are intended to be covered by the appended claims.

What I claim is:

1. In a. thread grinding machine, the combination with a work car ing spindle, a lead screw aligned with an connected to said spindle, means for rotating the screw and said spindle in a forward and a reverse direction while permitting axial movement thereof, a stationary nut for engaging said screw to effect axial movements of the screw and the spindle, and a rotating grinding wheel for engaging the work carried by the spindle, of means automatically controlled in accordance with the axial movements of the spindle for reversing the direction of rotation of the spindle and for effecting feeding movement by the wheel,'means for stopping the operation of the machine after a predetermined number of reversals in the direction of rotation of the spindle, and means for varying the number of reversals of the spindle rotation before operation of said automatic stoppingmeans.

2. In a thread grinding machine, the combination with a work carrying spindle, a lead screw aligned with, and connected to, said work spindle, and means 4for rotating the screw and spindlef while permitting axial movement thereof, of a two-piece nut mounted on said screw, means for holding the nut against rotation and axial movement while permittin the rotation of the screw therein, means for relatively adjusting the two parts of the nut, and means for so connecting the screw to the rotating meansand to the spindle as to permit a quick removal and replacement of a screw and the nut mounted thereon.

3. In a thread grinding machine, the combination with a carriage, a work carrying spindle mounted on said carriage, a lead screw aligned with and connected to said spindle, means for rotating the screw and the spindle in a forward and in a reverse direction while permitting axial movement thereof, and a stationaryi nut engaging said screw7 for effecting axial movement of the carriage and work, of means controlled by the carriage movement for reversing the rotation of said lead screw, and means controlled by the carriage movement for stopping the operation of the machine upon a predetermined number of movements of the carriage.

4. In a thread grinding machine, the combination with a carriage, a work carrying spindle mounted on said carriage, a. lead .screw yaligned with and connected to said spindle, means for rotating the screw and the spindle in a forward and a reverse direction while permitting axial movement thereof, and a stationary nut engaging said screw for effecting axial movement of the carriage and work, of means controlled b dogs on said carriage for reversing the d1- rection of rotation of the screw to effect movement of the carriage, a rotating grinding wheel for enga ing the work, means automatically control ed by dogs on the carriage for effecting feeding movements by the grindin wheel, and means automatically controlled stopping the operation of the machine upon a predetermined number of carriage movements.

5. In a thread `grinding machine, the combination with a work carrying spindle, a lead screw aligned with, and connected to, said spindle, and means for rotating the screw and said spindle in a forward and a reverse direction while permitting axial movement thereof, of a stationary nut engaging said screw to effect axial movement of the screw and the spindle, means for automatically reversing the direction of rotation ofthe spindle upon a predetermined axial movement thereof, and means for automatically stopping the operation of the machine upon a predetermmed number of reversals of the spindle rotation.

6. In a thread grinding machine, the combination with a work carrying spindle, a lead screw aligned with, and connected to, said spindle, and means for rotating the screw and said spindle in a forward and a reverse direction while permitting axial movement thereof, of a stationary nut engaging said screwfor effecting axial movement of the screw and the spindle, means for automatically reversing the direction of y the carriage movement forl rotation of the spindle upon` a predetermined axial movement thereof, means for automatically stopping the operation of themachine upon a predetermined number o reversals o for varying the number of reversals elected by the spindle before operationvof said automatic stopping means.

7.' In a thread grinding machine, the bomhina/tion with a work carrying spindle, a lead screw aligned with said work s indle, and means comprisin a work shaft or rotating the screw an spindle while permitting axial movement thereof, of a twothe spindle rotation, and means- .movement while permitting the rotation of the screw therein, means for relatively ad- .j-usting the two parts of the nut, and means fordisconnecting the nut from the holding means and for disconnecting the screw from the work shaft and the spindle to permit a quick removal and replacement of a screw and the nut mounted thereon. y

In testimony whereof, I hereto aix my signature.

HENRY E. DURKEE. 

